There are a lot of benefits to being married: tax breaks, legal protections, easier home loans. But it turns out a healthier life isn’t one of them, as long as you’re living together.

A study of 10,000 people published in the August issue of the American Journal of Public Health found that unwed couples cohabitating in middle age had the same level of health as those who made their relationships legally binding. (As a commenter on the Ars Technica coverage astutely noticed: “So our bodies can’t tell whether or not we have signed a license or held a ceremony?”) The pool was measured by their blood and inflammatory biomarkers and respiratory capacity, taking into account variables like income, education, and employment.

Interestingly, while single men suffered big declines in health, women who kept playing the field saw little decline. Something about fish needing bicycles.

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